Possible Use of Polar Body for Infertility Treatment

Highlights

• Polar bodies are produced during the maturation of the immature egg and are discarded by the body.
• Researchers introduced the polar bodies formed during the first cell division into oocytes without nuclear material to produce functional embryos.
• The process has the potential to double the number of mature eggs available for in vitro fertilization and thereby improve the success rate of the procedure.

Researchers at the Oregon Health & Science University and the Salk Institute for Biological Studies found that polar bodies released from oocytes during maturation can be used in the treatment of infertility in women. The study was published in the Cell Stem Cell. The polar body is formed during cell division of the immature egg cell called primary oocyte. During the cell division, two cells are formed with equal distribution of the genetic material in the nucleus, but in-equal distribution of the cytoplasm, the jelly-like substance that surrounds the nucleus. Therefore, two dissimilar cells are formed – the larger one is called the secondary oocyte, while the smaller cell is called the primary polar body. Both cells undergo a further cell division, the primary polar body divides into two polar bodies, while the secondary oocyte gives rise to the mature egg or mature ovum and another polar body. Thus, during the process of formation of a mature ovum from an immature egg, three polar bodies are formed. These polar bodies are later destroyed and are therefore of no use to the body.

Researchers investigated the use of polar bodies in the treatment of infertility. The research team took out the nucleus which contains the genetic material from a donor oocyte and introduced the first polar body genome obtained from a woman’s developing oocyte.

To find out if the eggs were functional, the researchers went to the extent of fertilizing the newly formed oocytes with sperms. The eggs completed their cell division following the fertilization, which resulted in the formation of viable embryos. However, they did not go beyond this point and allow the embryos to develop into pregnancies.

The research is in its very initial phase, but if it progresses in the right direction, it may be a help to numerous women with infertility. Women who are particularly likely to benefit from this treatment are those who wish to get pregnant at an older age. Older women experience reduced fertility. This process could double the number of eggs produced for in vitro fertilization, and therefore increase the chances of having a baby.

This treatment could also be potentially useful in those women who have serious genetic diseases of the mitochondria that could interfere with the normal development of the baby.

Though it is a step forward in the treatment of fertility, this technique can be put into use only after it has been repeatedly tested and all the implications of the process have been understood.

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Reference:

1. Ma H et al. Functional Human Oocytes Generated by Transfer of Polar Body Genomes. DOI: - (http://dx.doi.org/10.1016/j.stem.2016.10.001)

Source-Medindia